(i) Field of the Invention
The invention relates to vacuum operated refuse collecting vehicles and more particularly to vacuum operated refused collecting vehicles of the kind comprising an air-tight container mounted on the chassis of the vehicle and having an outlet communicating with means for generating a vacuum within the container and a suction conduit for each side of the vehicle, each suction conduit extending at one end into the interior of the container and being provided at the other end with a nozzle which may be disposed at a short distance from the ground.
(II) Prior Art
Known refuse collecting vehicles of the kind described above generally are designed so that the container is approximately centrally positioned over the rear axle of the vehicle chassis and the container is usually pivoted about a transverse pivotal hinge at its rear so that the container may be tipped up to discharge its contents by gravity. An openable rear door is provided in the container for this purpose.
In normal use of the vehicle, one of the suction conduits is closed off and the vacuum generating means induces a fast flowing airstream through the other suction conduit which sucks refuse into the container.
Various arrangements for the suction conduit inlets to the container, the means to close them off and the suction outlet from the container have been proposed. In one known arrangement, the inlets from the suction conduits are positioned towards the front of the container in its lower part and the outlet is at the rear upper part of the container. In this arrangement, the interior upper wall of the container is concavely curved so that the refuse laden airstream entering via the suction conduit which is in use flows up one side of the container, around the top and down the other side, thence eventually to the outlet. This has the disadvantage that refuse carried by the air stream tends to be deposited at the side of the container opposite to the inlet in use, on and around the suction conduit which is not in use. This deposit of refuse results in uneven loading of the container and further may result in the suction conduit which is not in use becoming blocked by the pile of refuse. This problem is compounded by the fact that the spare suction conduit in such machines is usually closed off by a blanking plate inserted in the suction conduit at a point intermediate its ends so that the end of the conduit projecting into the container may become filled with refuse.
In other known arrangements, blanking plates for the suction conduits are provided which are slidably or pivotally mounted at the end of the respective suction conduit projecting into the container and thus prevent refuse from entering the spare suction conduit during operation of the vehicle. However, in these other known arrangements, the outlet from the container consists of an orifice extending along the centre line of the upper part of the container and this has the disadvantage that refuse-laden air entering the container through the suction conduit which is in use, tends to pass directly to the outlet. This is unsatisfactory because it is essential for the effective operation of vacuum operated refuse collecting vehicles of this type that the refuse laden air stream is induced to travel through the maximum distance possible within the container so that expansion and slowing down of the air stream allows the refuse to drop out of the air stream before the air reaches the outlet from the container. Attempts have been made to introduce baffles into vehicles having this last-described arrangement in order to divert the incoming air stream away from the outlet but none of these attempts has been very successful.